Chilton Medical Center - ATLANTIC HEALTH SYSTEM
Decrease (-) Restore Default Increase (+)  font size
PrintEmail
Search Health Information   

Genetics
Genetics


Sex-linked dominant

Definition:

Sex-linked dominant is a rare way that a trait or disorder can be passed down through families. A single abnormal gene on the X chromosome can cause a sex-linked dominant disease.

Related terms and topics:



Alternative Names:

Inheritance - sex-linked dominant; Genetics - sex-linked dominant; X-linked dominant; Y-linked dominant



Information:

Inheritance of a specific disease, condition, or trait depends on the type of chromosome affected (autosomal or sex chromosome). It also depends on whether the trait is dominant or recessive. Sex-linked diseases are inherited through one of the sex chromosomes (the X or Y chromosome).

Dominant inheritance occurs when an abnormal gene from one parent is capable of causing disease, even though a matching gene from the other parent is normal. The abnormal gene dominates the gene pair.

For an X-linked dominant disorder: If the father carries the abnormal X gene, all of his daughters will inherit the disease and none of his sons will have the disease. That is because daughters always inherit their father's X chromosome. If the mother carries the abnormal X gene, half of all their children (daughters and sons) will inherit the disease tendency.

In other words, if there are four children (two males and two females) and the mother is affected (one abnormal X, she has the disease) but the father is not, the statistical expectation is for:

  • Two children (one girl and one boy) with the disease
  • Two children (one girl and one boy) without the disease

If there are four children (two males and two females) and the father is affected (abnormal X, he has the disease) but the mother is not, the statistical expectation is for:

  • Two girls with the disease
  • Two boys without the disease

This does not mean that the children will necessarily be affected.




Review Date: 5/16/2012
Reviewed By: Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
adam.com


Morristown Medical Center
100 Madison Avenue
Morristown, NJ 07960
973-971-5000

Overlook Medical Center
99 Beauvoir Avenue
Summit, NJ 07901
908-522-2000

Newton Medical Center
175 High Street
Newton, NJ 07860
973-383-2121

Chilton Medical Center
97 West Parkway
Pompton Plains, NJ 07444
973-831-5000

Goryeb Children's Hospital
100 Madison Avenue
Morristown, NJ 07960
973-971-5000

© 2014 Chilton Medical Center, 97 West Parkway, Pompton Plains, New Jersey 1-973-831-5000